>The WD RE4-GP is a so-called ''green'' disk that's suitable for RAID >arrays. It's marketed and priced as an enterprise drive. I've had good luck with green, 5400 rpm Samsung drives. They don't spin down automatically and work fine in my raid 5 arrays. The cost is about $80 for 2TB drives. I also have a few 5900 rpm Seagate ST32000542AS drives, but not currently in raids. They don't spin down, so I'm sure they would be fine in a raid. None of the drives in the raids have failed, although I've replaced a couple that developed reallocated sectors as reported by smart. Just because they are so tiny on the outside, 2.5 inch drives like the Seagate Constellation and WD Raptors are great. Unfortunately, the don't come any larger than 1TB, so I use them in special situations.